Label printers are known to the prior art for printing a succession of characters, which may be human-readable characters or machine-readable characters such as bar code characters, on a succession of labels which removably adhere to an elongated strip of label stock backing. These printers may be of the mechanical impact type in which printing is accomplished by mechanically impacting the label stock and an interposed ink ribbon against a raised print element on a rotating print wheel, or may be of the thermal type in which printing is accomplished by selectively heating the label to expose a thermally responsive layer thereon. In such printers, the label stock is moved past a print station where the characters are successively printed. After printing, the label stock is moved along various paths, depending upon the construction of the printer and the desired application. One of these paths may be termed a "spooling" path, in which the label stock is simply wound onto a take-up reel for subsequent dispensing of the printed labels. Another of these paths may be termed a "self-strip" path, in which each label is partially separated from the backing strip by a label stripping apparatus so that the label can be completely removed from the backing strip by hand and in which the backing strip is wound onto a take-up reel. Yet another path may be termed a "nonspooling" path, in which both the labels and the backing strip exit the printer without label separation.
In those prior label printers that accommodate both the nonspooling and self-strip paths, a drive capstan and a pinch roller are located downstream of the print station and separated therefrom by a considerable distance. When the label stock is to be moved along the nonspooling path, the label stock is passed directly to and threaded between the drive capstan and pinch roller. When the label stock is to be moved along the self-strip path, the label stock is first passed over the label stripping apparatus so that the label stock sharply changes its direction, then passed over an idler roller, and then passed to and threaded between the drive capstan and pinch roller.
This structure makes such label printers somewhat difficult to use. In the nonspooling path, the label stock must be moved by an amount equal to the separation between the print station and the drive capstan and pinch roller before any printed label can exit the printer. As a result, a printed label cannot be viewed until a number of blank labels are advanced through the print station. In the self-strip path, a printed label can be removed from the backing strip only by reaching into the printer.
The present invention is therefore directed to the provision of a single mechanism that accommodates both the nonspooling and self-strip paths of label stock movement in a manner such that any printed label may exit the printer immediately after passing through the print station.